Hydrolysis of aluminum chloride sludge



Jan. 14, 1941. ROBERTS ETAL 2,228,707

HYDRoLYsIs 6F ALUMINUM cHLoRIDE SLUDGE Filed oct. 1e, 1959 Patented Jau.14, 1941 UNITED STATES PATENT OFFICE nrnaonrsxs or ALUMINUM cnLoamEswoon Pennsylvania Application October 16, 1939; Serial No. V299,778

i Claims.

Our invention relates to improvements in hydrolyzing4 certain aluminumchloride sludges, such as result from reacting hydrocarbon oils with orin the presence of aluminum chloride at 5 relatively low or moderatelyelevated temperatures.

In reiining lubricating oils with anhydrous alul minum chloride, forexample, the aluminum chloride reacts with undesirable hydrocarbonconstituents of a lubricating oil stock to form a viscous sludgecomprising mainly a mixture of double compounds of aluminum chloride andhydrocarbons, insoluble in the thereby rened oil,

' and having a melting point (ring and ball method) of from around 160to around 200 F.

Somewhat similar sludges also result from operations in which othertypes of hydrocarbon oils are reacted in the presence of aluminumchloride 26 at low, or moderately elevated temperatures, suchasalkylation and condensation processes, except that the sludges derivedfrom such process are usually of somewhat llower melting point and thehydrocarbons present 'therein are, in general, lower boiling than is thecase with respect to brlcatlng oils and-other heavy oils with aluvminumchloride.

'I'hese aluminum chloride sludges or residues having melting points notexceeding 200 F. are 30 to be snai-pw distingmshed from aluminum cmorideresidues produced in operations conducted at higher temperatures; forexample, still residues produced in the distillation or cracking ofhydrocarbons in the vpresence of aluminum chloride. In this latter typeof sludge, suoliy residues or sludges derived from high temperaturealkylations have correspondingly high melting` points, thehydrocarbons-present having frequently undergone carbonization. Theycannot easily be rendered iiuid and our inventionis not applicable tosuch sludges, although they have been successfully hydrolyzed to someextent in other ways.

The disposition and recovery of more ilui lower-melting-point residues,to the recovery of which our invention is addressed, has for years lconstituted a very serious problem, especially with respect to thesludges produced in the treatment of lubricating oils. Aluminum chloridehas' been used as a refining agent for lubricating oils, particularlythose .derived from Pennsylvania crudes, to a very large extent for anumber of years, so that the amounts. of sludge produced areconsiderable.

Although ii; has been knownfor years that residues resulting from thetreatment of v111-'.

(c1. ias-14s) all aluminum chloride-hydrocarbon sludges aretheoretically hydrolyzable, no satisfactory method of disposing of thesesludges had been evolved prior to our invention. These sludges whencooled do not hydrolyze in cold water. Attempts 45 have been made tohydrolyze them in tanksv with hot water, but have not been successful.As soon as the temperature reaches the point where hydrolysis commences,the action is very vigorous and large quantities of hydrochloric acidfumes 10 are evolved. From a practical standpoint it is impossible toarrest this vigorous hydrolysis once it has started. Consequently suchoperations have been abandoned, due to the lack of control and theserious hazards involved, due mainly to 15 the tremendous evolution ofhydrochloric acid fumes.

' Prior attempts at hydrolysis of these sludges were ln fact sounsuccessful and impracticable that for a number of years it' has beenthe custom to dispose of these residues or sludges by burning them onopen dumps. The hot, liluid residue leaving the oil treating vessels orkagitators was run into cars andl transferred to a largedump where thecars (with considerable 25 diillculty) were unloaded, and where theburning was to take place. However, these sludges burn very slowly andwith great diiiiculty, due to the tact that ascombustion proceedsadeposit of aluminum oxide forms over the surface of the burningmaterial. This deposit greatly interferes with combustion. As a resultit takes an excessively long time for a given amount of such sludge toreach a completely burned and inactive state on a dump. In one largeplant where 35 around 1300 carloads of sludge have been dumped forburning over a long period; only about half of the material dumped thusfar has been burned. It is necessary to rake over the dump heap atfrequent intervals to facilitate combustion, and duringdamp or rainyweather tremendous quantities of acid fumes are evolved.

It can readily be seen that an operation of this character is expensiveand wasteful and constitutes a serious nuisance VSuch a method ofdisposal would never have been adopted or used had any successful methodof hydrolysis been available. g

Our present invention has made it lpossible to overcome thedisadvantages and dimculties of prior methods of disposing of aluminumchloride vsludges of the character indicated and, furthermore, has madeit possible to recover the hydrocarbons present in such sludges in theform of a valuable product, i. e., as a heavy but not too 55 f viscousolsufficiently low in ashand acid contively large quantity. The ilowingstream of water containing the added sludge is then passed through apipe sufficiently long to permit substantial completion of hydrolysiswithin the pipe, and is delivered to a collecting vessel, whereseparation occurs. The water containing small amounts'of dissolvedaluminum chloride is withdrawn, preferably at a rate corresponding tothe rate of its introduction into the separating vessel, while theliberated vhydrocarbons remain in the separating vessel. After thesludge has all been withdrawn from the original contacting vessel,hydrolyzed and transferred into the separating vessel, the ilow of wateris terminated and all water is removed from the separating vessel. Adiluent oil is then introduced into the separating'vessel, where it isagitated with the hydrocarbons liberated from the sludge until kacondition of substantial homogeneity has been reached. 'I'he resultantfuel oil is then withdrawn from the separating vessel for use asdesired.

We have found that if the diluent oil is added to the separating vesseleither before or during the time of transfer of the sludge thereto,emulsion troubles are likely to be encountered in most cases. Therefore,the diluent oil is not added to the separating vessel until the entirehydrolyzing and transferring operation has been completed and the waterhas been withdrawn from the lat.l

ter as completely as possible. Enough diluent, of -a sumciently fluidcharacter, is then added to reduce the viscosity of the ilnal fuel oilproduct to a suitable point or to reduce the-ash content of the finaldiluted oil to whatever point is desired o r both. It is also importantto dilute the .liberated hydrocarbons sufficiently to permit separationfrom any residual water which may remain therein after the primary waterseparation stage.

The amount of water required is considerably in excess of that of thesludge and is governed largelyby the character and temperature of thesludge. Enough water is added, at a suillciently high temperature, notmerely to supply that theoretically necessary for hydrolysis but also tocontrol the temperature and to insure that hydrolysis will besubstantially completed before the flowing stream reaches the separatingvessel, so

that liberation of acid fumes from the separating vessel may be avoided.Ordinarily we employed from 3 to 'l parts by volume of water for eachpart by volume of sludge, and the water is introduced to the sludge at atemperature of from 100 to 125 F. (the sludge being at 225 to 270 F.),in order'to maintain a temperature of from 150 to 200 F. at the pointwhere the resultant stream of water and sludge reaches the separatingvessel.

The manner of mixing is important. While vaious types of apparatus mayperhaps be employed, we have secured exceptionally satisfactory resultsby using a mixing nozzle of the vtype commonly used v for mixingfoam-producing chemicals with water for the purpose of making.nre-extinguishing foams. Such a nozzle, frequently referred to as anejector, is provided with a central chamber having a side inlet throughwhich the sludge may be introduced. A stream of water enters the centralchamber through a more or less restricted nozzle at right angles to theentering flow of sludge, and the combined flow of water and sludgepasses out through a second nozzle of Venturi4 type. i Such a nozzle isideally suited Vfor the purposes of our invention.

In order that our invention may be more fully set forth and understood,we now describe, with reference to .the drawing accompanying and 15forming part of this specification, a preferred manner inI which it maybe practiced and embodied. In the drawing,

Fig. 1 is a more or less diagrammatic elevational view of an apparatusfor treating hydrocarbon lubricating oil stock with anhydrous aluminumchlorldeand forl effecting hydrolysis and recovery of the sludge therebyproduced;`and

Fig. 2 is a vertical sectional view of a form of nozzle Valsoillustrated in Fig. 1 and useful in the performance of our invention.

Similar reference numerals designate similar parts in both views of thedrawing.

Referring now to the drawing, and more particularly Fig. 1 thereof, rawlubricating oil stock to be rened is introduced through a valve line Ito a treating vessel 2, of conventional type. The vessel 2 is providedwith an agitating device 3 of suitable type.

After a suitable quantity of oil has been introduced into the vessel 2,aluminum chloride is added and the oil and aluminum chloride areagitated together. A vigorous reaction takes place, the aluminumchloride reacting with undesirable constituents of the stock (mainly ofan unsaturated, naphthenic or aromatic char acter) resulting in theformation of a double compound of aluminum chloride and the reactedconstituents: this sludge is insoluble in the reilned paraillnic oil andmay readily be separated therefrom at the temperatures which obtain atthe end of the treatment. 'Ihese arel usually in excess of 225 F. Atypical sludge produced in an operation of this kind, in whichPennsylvania lubricating stockris renned with aluminum chloride, has amelting point of from about .16'0I to about 190 F., and subsists at a Inaddition to a valve 1, the line 5 is prefer-ably provided with anorifice or sight-hole 8, whereby the flow of sludge through the line 5may be observed and controlled. Water is introduced tothe nozzle 6through a line 9, which may be provided with a pump I0,

and where necessary, steam is also supplied to the line 9 through avalved inlet Il in sufficient quantity to bring the temperature ofthewater entering the mixing nozzle 6 to the desired point. In a typicalinstance we have employed 5 parts by volume of water and condensedsteam, at a temperature of about 108 F., for each part of aluminumchloride sludge leaving the treating vessel 2 at a temperature ofabout`250 F.

at the discharge point. I

After passing through the line I2, the mixture of oil and sludge, inwhich hydrolysis has now taken place, enters a separating vessel I5, Asshown in the drawing, this vesselv I5 may be substantially similar inconstruction to the treating vessel 2, and is also provided with'agitating means I6 of conventional type. Under ordinary circumstances,however, little or no agitation is provided during the time of transfer-of sludge into the vessel I5, for it is found that separation takesplace immediately. The liberated hydrocarbons separate into an upperlayer, While the Water (containing liberated and dissolved aluminumchloride) settles to the bottom of the vessel and is withdrawn through aline II and a valved branch line I8. In a typical instance, the waterthus withdrawn has a pH value of about 2.5 and can be discarded withoutdimculty.

After all the sludge has been transferred from the agitator 2 into thevessel I5, the flow of water and steam is shut o, and the remainingwater is withdrawn as far as possible from the bottom of the vessel I5.The valved line I8 isthen closed and diluent oil is introduced by means'of a pump I9 and a line 20 into the separating vessel I5. Variousquantities and types of hydrocarbon oils may be used for dilutingpurposes, depending upon the desired characteristics of the final fuelproduct. Ordinarily, however, We have found that the addition of one Ibarrel of solar oil per three barrels of liberated hydrocarbons from thesludge gives satisfactory results.

After addition of the diluent oil, the mixture of liberated hydrocarbonsand diluent is agitated for a brief period to insure thorough mixing asWell as separation of any. small quantities of water which may remain.Such water, when necessary, is removed through the valved line I8, afterwhich the fuel oil product is removed through a valved branch line 2Iand transferred to storage or to fuel burners.

In a typical instance in which one part by weight of solar cil was addedper 5 parts by weight of liberated hydrocarbon'tar, there was produced afuel oil having the following characteristics:

G'ravity v132:1" API Viscosity (furol) 54 seconds at 122 F.

Flash 230 F.

Pour point v 0 F. Water and sediment 15% Sediment by extraction 11.7%

Carbon residue 13.39%

.Ash 0.38%

Acid about 0.0003% tent and the like may readily be obtained byjudicious blending with proper diluents. Some dilution is almost alwaysnecessary, however, f

on account of the high viscosity and high melting point of the releasedhydrocarbons, when in undiluted form.`

While we have described our invention hereinabove with respect tovarious operating details, it will be readily understood by thoseskilled in the art that our invention is not vlimited to such detailsbut may be variously .practiced and embodied within thel scope of theclaims hereinafter made.

What we claim is: y

1. In the treatment and disposal of aluminum chloride-hydrocarbonsludges which melt at temperatures of not more than about 200 F. andareproduced in treating hydrocarbons with i aluminum chloride at relativelylow temperatures, the improvement which comprises introducing saidsludge in a hot fluid condition into an enclosed flowing stream ofwater, passing the resulting mixture of sludge and water through anenclosed conduit of sumcient length and at such a rate that hydrolysisof thealuminum chloride is substantially complete when the 'mixturereaches the exit end of said conduit, delivering the thus hydrolyzedaluminum chloride, sludge and water to a vessel adapted to settle themixture and form an oily and an aqueous layer, and separately removingsaid aqueous and oily layers. 2. In the treatment and disposal ofaluminum chloride sludges which melt at temperaturesv of not more thanabout 200 F. and are formed in relatively low temperature refiningprocesses involving the treatment of petroleum oils with aluminumch1oride, the improvement which' comprises withdrawing said sludge fromthe reiining operation while it is still in a hot fluid condition andintroducing'the hot fluid into an enclosed flowing stream of Water,passing the resulting mixture of sludge and water through an enclosedconduit of sufficient length and at such a rate that hydrolysis of thealuminum chloride is substantially complete when the mix-.- ture reachesthe exit end of said conduit, delivering the thus hydrolyzed aluminumchloride,

sludge and water to a vessel adapted to settle the mixture and form anoily andan aqueous layer, and separately removing said aqueous and oilylayers.

3. In the treatment and disposal of aluminum chloride sludges which meltat temperatures of not more than about 200 F. and are formed inrelatively low temperature refining processes involving treatment ofApetroleum oils with alu-` minum chloride, the improvement whichcomprises withdrawing said sludge from the refining operation while itis still in a hot fluid condition and introducing the hot fluid into anenclosed owing stream of water, passing the resulting mixture of sludgeand water through an enclosed conduit and regulating the temperature ofthe water, rate of flow and length of the conduit such that thehydrolysis of the aluminum chloride is substantially complete when themixture reaches the exit end of ysaidv conduit. deliveringy the thushydrolyzed aluminum chloride, sludge and Water to a vessel adapted tosettle and separate the mixture into an oily and an aqueous layer, andseparately removing said aqueous and oily layers.

4. In the treatment and disposal of aluminum chloride sludges which meltat temperatures of not more than about 200 F. and are formedV in.

relatively low temperature rening'processes in- 4 volvingtreatment ofpetroleum oils with aluminum chloride, the` improvement which comlprises withdrawing said sludge from the reiining operation while it isstill in a hot fluid condition and introducing the hot uid into anenclosed flowing stream of water, passing the resulting mixture oisludge and water through an enclosed conduit and regulating thetemperature of the water, the rate/of ilow and length of the conduitsuch that the hydrolysis of the aluminum chloride is substantiallycomplete when the mixture reaches the exit end of said conduit,delivering the thus hydrolyzed aluminum chloride, sludge and water to avessel adapted to settle and .separate the mixture into an oily and anaqueous layer, removing the aqueous layer from said vessel, diluting theremaining oily layer with an oil,

and withdrawing the resulting oily mixture from said vessel.

, 5. In the treatment, and disposal of aluminum chloride sludges whichmelt at temperatures of not more than about 200 F. and are formed inrelatively low temperature refining processes involving treatment ofpetroleum oils with aluminum chloride,A the improvement which compriseswithdrawing said sludge from the refining operation while it is still ina hot iluid condition, introducing the hot iluid into a pipe connectedwith a chamber, exerting suction on said fluid in said'pipe and causingit to mix with water in said chamber by means of a stream 'oi' waterflowing through a nomle at right angles to said pipe into said chamberand out of said chamber through a Venturi nome at right angles to said-pipe, passing the` stream of sludge and water thus formed through anenclosed conduit, regulating the temperature oi' the water, the rate oiflow and the length of the conduit such that the hydrolysis of thealuminum chloride is substantially complete when the mixture reaches theexit end of said conduit, delivering the thus hydrolyzed aluminumchloride, sludge and water to a vessel adapted to settle and separatethe mixture into an oily and an aqueous layer, and separately removingsaid aqueous and oily layers.

6. In the treatment and disposal or aluminum chloride sludges which meltat temperatures oi not more than about 200 F. and are formed inrelatively low temperature refining of lubricating oil stock withaluminum chloride, the improvement which comprises withdrawing saidsludge from the refining operation while it is still in a hot tluidcondition and introducing the hot iluid into an enclosed ilowing streamof water, passing the resulting mixture of sludge and water throughan'enclosed conduit, regulating the temperature of the water, the lengthof the conduit andthe rate of flow lsuch that hydrolysis of the aluminumchloride is substantiallycomplete when the-mixture reaches the exit endof said l conduit, delivering the thus hydrolyzed aluminum chloride,sludge and water to a vessel adapted to settle and separate the mixtureinto and while in a hot iluid condition with from aboutl 3 to about 'I'times its volume of water maintained at a feed temperature of fromabout 100 to about 125 F., passing the resulting mixture through anenclosed conduit and regulating conditions of ilow and length of theconduit such that at the exit end of said conduit the hydrolysisof thealuminum chloride is substantially complete and the temperature of themixture lies between about 150 and about 200 F., delivering theresulting mixture toa vessel adapted to separate it into oily andaqueous layers,'removing the aqueous layer, diluting the oily layer withan oil and withdrawing the resulting oily mixture.

GERALD I. ROBERTS.

ALMER M. MCAFEE. OI'IO C. LOTT.

